Cell Morphology of the Blue-Green Algae Under Culture Conditions fromCycas RevolutaIsolated. II: An Electron Microscope Study

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Abstract
Colonies of the blue-green alga isolated from root nodules Cycas revoluta were grown under different light conditions. The cell features as observed in the electron microscope, are here reported. The vegetative cells, the heterocysts and the akinetes were observed. The photosynthetic apparatus of the vegetative cells of the cultures grown under room light conditions appeared of the reticular type, with structured, polyhedral, poliglucoside and polyphosphate granules, lipid globules and some particular « gamma » granules; the last ones were roundish, very electron opaque and prevalently localized in the centroplasm. These granules were evident after KMnO4 fixation. The vegetative cells of the colonies grown under continuous light showed an early generalized process of vacuolisation and keritomie and contained polyglucoside and structured granules, lipid globules and cavities delimited by a fine dark membrane. Several of these bodies contained a granular substance (vacuolar granules), and were interpreted as polyphosphate granules in different stage of evolution. These results show, in agreement with the observations with the optical microscope, that light can markedly affect the ultra structural morphology of these blue-green algae.